1. Field of the Invention
The present invention relates to an information processing device and method, and information processing system, and particularly, relates to an information processing device and method, and information processing system whereby with data transfer of contents, increase in unnecessary delay time can be suppressed, and unnecessary deterioration of quality as contents can be suppressed.
2. Description of the Related Art
Heretofore, as a video picture transmission/reception device, there has been a triax system employed for sports relay broadcasting or the like at a broadcasting station or stadium. Triax systems which have been employed so far have been primarily for analog pictures, but along with recent digitization of image processing, it can be conceived that digital triax systems for digital pictures will become widespread from now on.
With a common digital triax system, a video picture is captured at a camera head and sent to a transmission path (main line video picture), and the main line video picture is received at a camera control unit and output to a screen. A camera control unit user gives instructions to the camera head user, relating to shooting. The camera head user performs shooting based on the instructions thereof.
The camera control unit also sends a return video picture to the camera head side using another system separate from the main line video picture. This return video picture may be a result of the main line video picture supplied from the camera head being converted, or may be a video picture externally input at the camera control unit. The camera head outputs this return video picture to the screen, for example. The camera head user can confirm, for example, how the shot image shot by himself/herself is received at the camera control unit by referencing the return video picture.
In general, the band of a transmission path between the camera head and camera control unit is limited, and accordingly, a video picture needs to be compressed to send this through the transmission path. For example, in a case wherein a main line video picture to be sent from the camera head toward the camera control unit is HDTV (High Definition Television) signals (current signals are around 1.5 Gbps), it is practical to compress these to around 1/10, around 150 Mbps. As for such a picture compression method, various compression methods, for example, MPEG (Moving Picture Experts Group) and so forth are available (see Japanese Unexamined Patent Application Publication No. 9-261633).
The above is the basic configuration and operation of the digital triax system. With such a digital triax system, the main line and return line which are transmission paths of a compressed stream are generally configured of a coaxial cable or the like, and the compressed stream is transmitted as a digital signal. Accordingly, it is desirable to transmit a compressed stream generally at a constant bit rate.
With a common encoding method, the bit rate of encoded data obtained by encoding, i.e., encoding rate is changed according to the image content of image data to be encoded (depending on difficulty of encoding). Accordingly, in order to transmit encoded data generally at a constant bit rate, there is the need to temporarily store encoded data obtained by encoding, and read out the encoded data stored in the buffer at a constant bit rate, thereby smoothing the bit rate.
At this time, in order to further stabilize (smooth) the bit rate at the time of transmission of the encoded data, it is desirable to accumulate encoded data in the buffer as much as possible. Also, encoded data is accumulated in the buffer as much as possible, thereby improving compression efficiency as well.